Humans have driven the northern white rhino to extinction, but scientists may be about to pull off the impossible and save the species.

Human poachers have driven many animals to extinction over the centuries and, until recently, it seemed as if the northern white rhino was about to experience the same fate. Currently, there are only two known to still be alive, both of which are female and unable to bare offspring.

However, veterinarians and conservationists have announced the successful harvesting of eggs from the rhinos, named Najin and Fatu, who now live at the Ol Pejeta Conservancy in Kenya. This is the first time that the complicated process has been attempted in northern white rhinos.

The harvested eggs will be artificially inseminated with frozen sperm from a now-deceased northern white rhino bull. In the near future, the veterinarians will transfer the embryo to a southern white rhino surrogate mother.

“Both the technique and the equipment had to be developed entirely from scratch,” said Prof Thomas Hildebrandt from the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) in Berlin and Dr David Ndeereh from the Kenya Wildlife Service (KWS), who headed the procedure.

“We were able to harvest a total of 10 oocytes – five from Najin and five from Fatu – showing that both females can still provide eggs and thus help to save these magnificent creatures.”

‘A wonderful success’

The first-of-its-kind procedure to harvest the oocytes (immature egg cells) was conducted with a probe, which was guided by ultrasound to extract the cells from the ovaries of the animals placed under general anaesthetic.

The procedure took place as part of an international research project named ‘BioRescue’. As well as harnessing the collective knowledge and expertise of the consortium’s partners to conduct the in vitro procedure, the project will also lead the development of techniques and procedures to create artificial gametes from stem cells.

This will involve transforming stored tissue from northern white rhinos into induced pluripotent stem cells, and then into primordial germ cells. These germ cells can then by developed into eggs or sperm cells, essentially widening the species’ genetic basis.

Jan Stejskal from Dvur Kralove Zoo in the Czech Republic – where the two rhinos were born – said the procedure was “a wonderful success”, adding that such work “can lead to hopeful prospects even for the animals that are imminently facing extinction”.